Organic electroluminescence device, organic thin film, and triamine compound

ABSTRACT

The present invention provides a triamine compound represented by general formula (I): ##STR1## an organic luminescence device which comprises an organic layer and a pair of electrodes disposed on both sides of the organic layer wherein the organic layer at least contains a layer of a light emitting zone and a layer of a hole transporting zone which comprises a hole injecting layer containing the triamine compound and a hole transporting layer, and an organic thin film comprising two layers which are a layer containing a compound represented by general formula (I) and having a thickness of 5 nm to 5 μm and a layer containing a compound represented by general formula (II): ##STR2##

TECHNICAL FIELD

This application is a 371 of PCT/JP 96/00082 filed Jan. 19, 1996.

The present invention relates to an organic electroluminescence device,an organic thin film, and a triamine compound. More particularly, thepresent invention relates to an organic electroluminescence device whichhas little possibility of dielectric breakdown after storage for a longtime and shows a remarkably increased efficiency of light emissionbecause a specific triamine is used in the hole injecting layer, anorganic thin film which shows very excellent hole injecting andtransporting properties and is advantageously used for the organicelectroluminescence device and photosensitive films in the electronicphotography, and a triamine compound which provides an organicelectroluminescence device having a long life and showing an excellentstability of light emission when the triamine compound is used for thedevice.

BACKGROUND ART

Electroluminescence devices which utilize the electroluminescence showhigh self-distinguishability because of the self-emission and areexcellent in impact resistance because they are completely soliddevices. Therefore, electroluminescence devices have been attractingattention for application as light emitting devices in various types ofdisplay apparatus.

The electroluminescence devices include inorganic electroluminescencedevices in which an inorganic compound is used as the light emittingmaterial, and organic electroluminescence devices in which an organiccompound is used as the light emitting material. Organicelectroluminescence devices have been extensively studied for practicalapplication as a display device of the next generation because theapplied voltage can be decreased to a large extent.

As for the construction of the organic electroluminescence device, thebasic construction comprises an anode/a light emitting layer/a cathode.(This description shows that an anode, a light emitting layer, and acathode are laminated in this order. Other constructions are describedin the same manner.) Constructions having a hole injecting andtransporting layer or an electron injecting and transporting layersuitably added to the basic construction are known. Examples of suchconstruction include the construction of an anode/a hole injecting andtransporting layer/a light emitting layer/a cathode and the constructionof an anode/a hole injecting and transporting layer/a light emittinglayer/an electron injecting and transporting layer/a cathode. The holeinjecting and transporting layer has the function of transporting holesinjected from the anode to the light emitting layer. The electroninjecting and transporting layer has the function of transportingelectrons injected from the cathode to the light emitting layer. It hasbeen known that, when the hole injecting and transporting layer isinserted between the light emitting layer and the anode, more holes areinjected into the light emitting layer in a lower electric field, andelectrons injected into the light emitting layer from the cathode or theelectron injecting and transporting layer are accumulated at theinterface between the hole injecting and transporting layer and thelight emitting layer because the hole injecting and transporting layerdoes not transport electrons. As the result, efficiency of the lightemission is increased.

Organic electroluminescence devices have a problem that, because anultra-thin film made of an organic compound is used in organicelectroluminescence devices, the thin film is crystallized to causedielectric breakdown after storage of the devices for a long time.

Heretofore, in organic electroluminescence devices, a phthalocyaninematerial is generally used at the interface with an anode as the holeinjecting material. The phthalocyanine material is a particularly easilycrystallizable material among organic materials used inelectroluminescence devices, and development of a hole injectingmaterial which can replace the phthalocyanine material and shows a highdegree of amorphous property has been desired.

To solve the above problem, a technology using an amine of the dendrimertype as the hole injecting material which can suppress the dielectricbreakdown in the device has been proposed (the specification of JapanesePatent Application Laid-Open No. Heisei 4(1992)-308688). However, thistechnology has a problem that the efficiency of light emission of theobtained device is low. A technology using an organic semiconductor ofthe oligomer type as the hole injecting material has also been disclosed(the specification of European Patent No. 439627). However, thistechnology is not suitable for practical application either because theefficiency of light emission of the obtained device is low.

Moreover, the above organic electric luminescence devices have a problemthat the luminance of the light emission is decreased after the deviceshave been driven continuously for a long time, and this problem isanother major obstacle for practical use of these devices.

In order to solve the above problems, a technology has been disclosed inwhich the generation of the leak current is prevented by using an amineof the dendrimer type, and the light emission can be maintained for along time with stability (the specification of Japanese PatentApplication Laid-Open No. Heisei 4(1992)-308688).

However, although this technology is effective for preventing theshort-circuit, the stability of light emission is still insufficient forthe practical application.

Accordingly, the present invention has an object of providing an organicelectroluminescence device which has little possibility of dielectricbreakdown after storage for a long time and shows a remarkably increasedefficiency of light emission by using a material which is not easilycrystallized as the hole injecting material, and an organic thin filmwhich shows very excellent hole injecting and transporting propertiesand is advantageously used for the organic electroluminescence deviceand photosensitive films in the electronic photography.

The present invention has another object of providing a novel compoundwhich provides an organic electroluminescence device having a long lifeand showing an excellent stability of light emission when the novelcompound is used for the device.

DISCLOSURE OF THE INVENTION

As the result of extensive studies to achieve the first object of thepresent invention described above, it was found that an organicelectroluminescence device in which a specific triamine is used as thehole injecting material has little possibility of dielectric breakdowneven after storage for a long time and shows a remarkably highefficiency of light emission. It was also found that an organic thinlayer comprising two layers which are a layer containing the specifictriamine compound and having a specific thickness and a layer containinga specific compound and having a specific thickness exhibits veryexcellent hole injecting and transporting properties.

It was also found by the present inventors that a novel triamine havinga specific structure containing an aryl group is advantageously used forachieving the second object of the present invention described above.

The present invention has been completed on the basis of the abovediscoveries.

Accordingly the present invention provides an organicelectroluminescence device which comprises an organic layer at leastcomprising a layer of a hole transporting zone and a layer of a lightemitting zone and a pair of electrodes disposed on both sides of theorganic layer, wherein the layer of a hole transporting zone at leastcomprises a hole injecting layer and a hole transporting layer, and thehole injecting layer contains a compound represented by general formula(I): ##STR3## [wherein Ar¹ to Ar⁵ represent each an aryl group having 6to 18 core carbon atoms which is unsubstituted or substituted with analkyl group, an alkoxy group, vinyl group, or styryl group, and may bethe same with each other or different from each other (the number ofcore carbon atom means the number of carbon atom forming an aromaticring among the carbon atoms of the aryl group)] and is in contact withan anode. Ar¹ to Ar⁵ in general formula (I) preferably represent each anaryl group having 6 to 18 carbon atoms which is unsubstituted orsubstituted with an alkyl group, an alkoxy group, vinyl group, or styrylgroup.

In the present invention, it is preferred that the hole transportinglayer in the electroluminescence device contains a compound representedby general formula (II): ##STR4## [wherein X represents a single bond,methylene group, phenylene group, biphenylene group, --O--, --S--, or agroup represented by any of: ##STR5## and Ar⁶ to Ar¹⁰ represent each anaryl group having 6 to 18 carbon atoms which is unsubstituted orsubstituted with an alkyl group, an alkoxy group, vinyl group, or styrylgroup, and may be the same with each other or different from eachother].

The present invention also provides an organic thin film comprising twolayers which are a layer containing a compound represented by generalformula (I) and having a thickness of 5 nm to 5 μm and a layercontaining a compound represented by general formula (II) and having athickness of 5 nm to 5 μm.

The present invention further provides a triamine compound representedby general formula (III): ##STR6## [wherein Ar¹ to Ar⁴ represent each anaryl group having 6 to 18 core carbon atoms which is unsubstituted orsubstituted with an alkyl group, an alkoxy group, vinyl group, or styrylgroup and may be the same with each other or different from each other,and Ar⁵ represents biphenyl group which is unsubstituted orsubstituted]. In this triamine compound, it is preferred that Ar⁵ ingeneral formula (III) represents an aryl group represented by: ##STR7##[wherein R represents hydrogen, an alkyl group having 1 to 6 carbonatoms, an alkoxy group having 1 to 6 carbon atoms, or phenyl group, nrepresents an integer of 0 to 5, and when a plurality of R are present,the plurality of R may be the same with each other or different fromeach other], and Ar¹ to Ar⁴ represent each an aryl group represented byany of: ##STR8## [wherein R¹ to R⁵ represent each hydrogen, an alkylgroup having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbonatoms, or phenyl group, m represents an integer of 0 to 5, p representsan integer of 0 to 4, q represents an integer of 0 to 5, x represents aninteger of 0 to 3, y represents an integer of 0 to 4, and when aplurality of R¹, R², R³, R⁴, or R⁵ are present, the plurality of R¹, R²,R³, R⁴, or R⁵ may be the same with each other or different from eachother].

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a whole chart of the ¹ H-NMR spectrum of4,4'-bis[N,N-di-(3-tolyl)amino]-4"-phenyl-triphenylamine obtained inExample 9.

FIG. 2 shows an enlarged detail of a part of the ¹ H-NMR spectrum if4,4'-bis[N,N-di-(3-tolyl)amino]-4"-phenyl-triphenylamine obtained inExample 9.

THE MOST PREFERRED EMBODIMENT TO CARRY OUT THE INVENTION

The organic electroluminescence device of the present inventioncomprises an organic layer at least comprising a layer of a holetransporting zone and a layer of a light emitting zone, and a pair ofelectrodes, i.e., an anode and a cathode, disposed on both sides of theorganic layer.

The anode in this electroluminescence device is an electrode used forinjecting holes into the device. As the anode, an electrode made of amaterial, such as a metal, an alloy, an electrically conductivecompound, and a mixture of these compounds, which has a large workfunction (4 eV or more) is preferably used. Specific examples of thematerial for the anode include metals, such as Au, and dielectrictransparent materials, such as CuI, ITO, SnO₂, and ZnO. The anode can beprepared by forming a thin film of the material described above by amethod, such as the vapor deposition and the sputtering. When the lightis obtained through the anode, it is preferred that the transmittance ofthe anode is larger than 10%. It is also preferred that the electricresistance of the sheet as the anode is several hundred Ω/□ or less.

The thickness of the anode is selected generally in the range of 500 nmor less, preferably in the range of 10 to 200 nm, although the thicknessdepends on the used material.

On the other hand, the cathode is an electrode used for injectingelectrons into the device. As the cathode, an electrode made of amaterial, such as a metal, an alloy, an electric conductive compound, ora mixture of these compounds, which has a small work function (4 eV orless) is used. Specific examples of the material for the cathode includesodium, sodium-potassium alloys, magnesium, aluminum, lithium,magnesium/copper mixtures, aluminum-lithium alloys, Al/Al₂ O₃ mixtures,indium, and ytterbium. The cathode can be prepared by forming a thinfilm of the material described above by a method, such as the vapordeposition and the sputtering. When the light is obtained through thecathode, it is preferred that the transmittance of the cathode is largerthan 10%. It is also preferred that the electric resistance of the sheetas the cathode is several hundred Ω/□ or less. The thickness of thecathode is selected generally in the range of 500 nm or less, preferablyin the range of 10 to 200 nm, although the thickness depends on the usedmaterial.

In the device of the present invention, it is preferred that at leastone of the anode and the cathode is formed with a transparent orsemi-transparent material. It is enabled by using such a material thatthe light is efficiently transmitted and obtained.

In the organic electroluminescence device of the present invention, thehole transporting zone means a zone generally showing a mobility ofholes of 10⁻⁶ cm² /V.s or more when an electric field of 10⁴ to 10⁶ V/cmis applied. In the present invention, the layer of the hole transportingzone at least comprises a hole injecting layer and a hole transportinglayer. It is necessary that the hole injecting layer contain a compoundrepresented by general formula (I): ##STR9## as the major component.

In above general formula (I), Ar¹ to Ar⁵ represent each an aryl grouphaving 6 to 18 core carbon atoms, preferably an aryl group having 6 to18 carbon atoms, which is unsubstituted or substituted with an alkylgroup, an alkoxy group, vinyl group, or styryl group, and may be thesame with each other or different from each other. As the alkyl groupand the alkoxy group, an alkyl group and an alkoxy group, respectively,having 1 to 6 carbon atoms are more preferable, and any of a linear,branched, and cyclic groups may be used. Examples of such an alkyl groupand an alkoxy group include methyl group, ethyl group, n-propyl group,isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butylgroup, various types of pentyl group, various types of hexyl group,cyclopentyl group, cyclohexyl group, methoxy group, ethoxy group,n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group,sec-butoxy group, t-butoxy group, various types of pentoxy group,various types of hexoxy group, cyclopentoxy group, and cyclohexoxygroup. When the aryl group having 6 to 18 core carbon atoms issubstituted, a single substituent or a plurality of substituents may beintroduced into the aromatic ring. The substituents may also be bondedtogether to form a ring. Examples of the aromatic ring in the aromaticgroup include benzene ring, naphthalene ring, acenaphthene ring,anthracene ring, fluorene ring, phenanthrene ring, pyrene ring, andbiphenyl ring. Ar¹ to Ar⁵ may be the same with each other or differentfrom each other.

Specific examples of the above compound represented by general formula(I) are shown in Table 1.

                                      TABLE 1-1A                                  __________________________________________________________________________    compound                                                                           Ar.sup.1    Ar.sup.2    Ar.sup.3                                         __________________________________________________________________________      HI-1                                                                                                       #STR10##                                                                      #STR11##                                                                      #STR12##                                          - HI-2                                                                                                    #STR13##                                                                      #STR14##                                                                      #STR15##                                          - HI-3                                                                                                    #STR16##                                                                      #STR17##                                                                      #STR18##                                          - HI-4                                                                                                    #STR19##                                                                      #STR20##                                                                      #STR21##                                          - HI-5                                                                                                    #STR22##                                                                      #STR23##                                                                      #STR24##                                          - HI-6                                                                                                    #STR25##                                                                      #STR26##                                                                      #STR27##                                          - HI-7                                                                                                    #STR28##                                                                      #STR29##                                                                      #STR30##                                          - HI-8                                                                                                    #STR31##                                                                      #STR32##                                                                     ##STR33##                                       __________________________________________________________________________

                  TABLE 1-1B                                                      ______________________________________                                        compound Ar.sup.4        Ar.sup.5                                             ______________________________________                                          HI-1                                                                                                   #STR34##                                                                      #STR35##                                              - HI-2                                                                                                #STR36##                                                                      #STR37##                                              - HI-3                                                                                                #STR38##                                                                      #STR39##                                              - HI-4                                                                                                #STR40##                                                                      #STR41##                                              - HI-5                                                                                                #STR42##                                                                      #STR43##                                              - HI-6                                                                                                #STR44##                                                                      #STR45##                                              - HI-7                                                                                                #STR46##                                                                      #STR47##                                              - HI-8                                                                                                #STR48##                                                                     ##STR49##                                           ______________________________________                                    

                                      TABLE 1-2A                                  __________________________________________________________________________    compound                                                                           Ar.sup.1        Ar.sup.2        Ar.sup.3                                 __________________________________________________________________________      HI-9                                                                                                               #STR50##                                                                      #STR51##                                                                      #STR52##                                  - HI-10                                                                                                           #STR53##                                                                      #STR54##                                                                      #STR55##                                  - HI-11                                                                                                           #STR56##                                                                      #STR57##                                                                      #STR58##                                  - HI-12                                                                                                           #STR59##                                                                      #STR60##                                                                      #STR61##                                  - HI-13                                                                                                           #STR62##                                                                      #STR63##                                                                      #STR64##                                  - HI-14                                                                                                           #STR65##                                                                      #STR66##                                                                      #STR67##                                  - HI-15                                                                                                           #STR68##                                                                      #STR69##                                                                      #STR70##                                  - HI-16                                                                                                           #STR71##                                                                      #STR72##                                                                     ##STR73##                               __________________________________________________________________________

                  TABLE 1-2B                                                      ______________________________________                                        compound                                                                             Ar.sup.4            Ar.sup.5                                           ______________________________________                                          HI-9                                                                                                     #STR74##                                                                      #STR75##                                            - HI-10                                                                                                 #STR76##                                                                      #STR77##                                            - HI-11                                                                                                 #STR78##                                                                      #STR79##                                            - HI-12                                                                                                 #STR80##                                                                      #STR81##                                            - HI-13                                                                                                 #STR82##                                                                      #STR83##                                            - HI-14                                                                                                 #STR84##                                                                      #STR85##                                            - HI-15                                                                                                 #STR86##                                                                      #STR87##                                            - HI-16                                                                                                 #STR88##                                                                     ##STR89##                                         ______________________________________                                    

                                      TABLE 1-3A                                  __________________________________________________________________________    compound                                                                           Ar.sup.1     Ar.sup.2     Ar.sup.3                                       __________________________________________________________________________      HI-17                                                                                                         STR90##                                                                       STR91##                                                                      #STR92##                                        - HI-18                                                                                                     #STR93##                                                                      #STR94##                                                                      #STR95##                                        - HI-19                                                                                                     #STR96##                                                                      #STR97##                                                                      #STR98##                                        - HI-20                                                                                                     #STR99##                                                                      #STR100##                                                                     #STR101##                                       - HI-21                                                                                                     #STR102##                                                                     #STR103##                                                                     #STR104##                                       - HI-22                                                                                                     #STR105##                                                                     #STR106##                                                                     #STR107##                                       - HI-23                                                                                                     #STR108##                                                                     #STR109##                                                                     #STR110##                                       - HI-24                                                                                                     #STR111##                                                                     #STR112##                                                                    ##STR113##                                    __________________________________________________________________________

                  TABLE 1-3B                                                      ______________________________________                                        compound Ar.sup.4         Ar.sup.5                                            ______________________________________                                          HI-17                                                                                                   #STR114##                                                                     #STR115##                                            - HI-18                                                                                                #STR116##                                                                     #STR117##                                            - HI-19                                                                                                #STR118##                                                                     #STR119##                                            - HI-20                                                                                                #STR120##                                                                     #STR121##                                            - HI-21                                                                                                #STR122##                                                                     #STR123##                                            - HI-22                                                                                                #STR124##                                                                     #STR125##                                            - HI-23                                                                                                #STR126##                                                                     #STR127##                                            - HI-24                                                                                                #STR128##                                                                    ##STR129##                                         ______________________________________                                    

                                      TABLE 1-4A                                  __________________________________________________________________________    compound                                                                           Ar.sup.1     Ar.sup.2     Ar.sup.3                                       __________________________________________________________________________      HI-25                                                                                                        #STR130##                                                                     #STR131##                                                                     #STR132##                                       - HI-26                                                                                                     #STR133##                                                                     #STR134##                                                                     #STR135##                                       - HI-27                                                                                                     #STR136##                                                                     #STR137##                                                                     #STR138##                                       - HI-28                                                                                                     #STR139##                                                                     #STR140##                                                                     #STR141##                                       - HI-29                                                                                                     #STR142##                                                                     #STR143##                                                                     #STR144##                                       - HI-30                                                                                                     #STR145##                                                                     #STR146##                                                                     #STR147##                                       - HI-31                                                                                                     #STR148##                                                                     #STR149##                                                                    ##STR150##                                    __________________________________________________________________________

                                      TABLE 1-4B                                  __________________________________________________________________________    compound                                                                            Ar.sup.4      Ar.sup.5                                                  __________________________________________________________________________      HI-25                                                                                             #STR151##                                                                     #STR152##                                                  - HI-26                                                                                          #STR153##                                                                     #STR154##                                                  - HI-27                                                                                          #STR155##                                                                     #STR156##                                                  - HI-28                                                                                          #STR157##                                                                     #STR158##                                                  - HI-29                                                                                          #STR159##                                                                     #STR160##                                                  - HI-30                                                                                          #STR161##                                                                     #STR162##                                                  - HI-31                                                                                          #STR163##                                                                    ##STR164##                                               __________________________________________________________________________

                                      TABLE 1-5A                                  __________________________________________________________________________    compound                                                                           Ar.sup.1           Ar.sup.2            Ar.sup.3                          __________________________________________________________________________      HI-32                                                                                                                     #STR165##                                                                     #STR166##                                                                     #STR167##                          - HI-33                                                                                                                  #STR168##                                                                     #STR169##                                                                     #STR170##                          - HI-34                                                                                                                  #STR171##                                                                     #STR172##                                                                     #STR173##                          - HI-35                                                                                                                  #STR174##                                                                     #STR175##                                                                     #STR176##                          - HI-36                                                                                                                  #STR177##                                                                     #STR178##                                                                     #STR179##                          - HI-37                                                                                                                  #STR180##                                                                     #STR181##                                                                    ##STR182##                       __________________________________________________________________________

                                      TABLE 1-5B                                  __________________________________________________________________________    compound                                                                            Ar.sup.4           Ar.sup.5                                             __________________________________________________________________________      HI-32                                                                                                  #STR183##                                                                     #STR184##                                             - HI-33                                                                                               #STR185##                                                                     #STR186##                                             - HI-34                                                                                               #STR187##                                                                     #STR188##                                             - HI-35                                                                                               #STR189##                                                                     #STR190##                                             - HI-36                                                                                               #STR191##                                                                     #STR192##                                             - HI-37                                                                                               #STR193##                                                                    ##STR194##                                          __________________________________________________________________________

In the electroluminescence device of the present invention, the holeinjecting layer may contain a single type or a combination of aplurality of types of the compound represented by general formula (I).It is necessary for achieving an efficient injection of holes that thehole injecting layer contain the compound represented by general formula(I), and it is also necessary that the hole injecting layer be disposedin contact with the anode. The thickness of the hole injecting layer isgenerally selected in the range of 5 nm to 5 μm.

On the other hand, the material used for the hole transporting layer inthe electroluminescence device of the present invention is notparticularly limited, and a material for a hole transporting layer whichis generally used in electroluminescence devices can be used. Examplesof the material for the hole transporting layer include triazolederivatives (such as those described in the specification of the U.S.Pat. No. 3,112,197), oxadiazole derivatives (such as those described inthe specification of the U.S. Pat. No. 3,189,447), imidazolederivatives, polyarylalkane derivatives, pyrazoline derivatives,pyrazolone derivatives, phenylenediamine derivatives, arylaminederivatives, amino-substituted chalcone derivatives, oxazolederivatives, styrylanthracene derivatives, fluorenone derivatives,hydrazone derivatives, stilbene derivatives, silazane derivatives,polysilanes, aniline copolymers, and electrically conductive polymers(particularly, thiophene oligomers).

Aromatic tertiary-amine compounds and styrylamine compounds can also beused as the material for the hole transporting layer. Representativeexamples of such compounds includeN,N,N',N'-tetraphneyl-4,4'-diaminophenyl,N,N'-diphenyl-N,N'-di(3-methylphenyl)-4,4'-diaminobiphenyl (TPDA),2,2-bis(4-di-p-tolylaminophenyl)propane,1,1-bis(4-di-p-tolylaminophenyl)cyclohexane,N,N,N',N'-tetra-p-tolyl-4,4'-diaminobiphenyl,1,1-bis(4-di-p-tolylaminophenyl)-4-phenylcyclohexane,bis(4-dimethylamino-2-methylphenyl)phenylmethane,bis(4-di-p-tolylaminophenyl)phenylmethane,N,N'-diphenyl-N,N'-di(4-methoxyphenyl)-4,4'-diaminobiphenyl,N,N,N',N'-tetraphenyl-4,4'-diaminodiphenyl ether,4,4'-bis(diphenylamino)terphenyl, N,N,N-tri(p-tolyl)amine,4,4'-bis[4-(di-p-tolylamino)stilbene],4-N,N-diphenylamino(2,2-diphenylvinyl)benzene,3-methoxy-4'-N,N-diphenylaminostilbene, and N-phenylcarbazole.

In the present invention, it is particularly preferred that a layercontaining a compound represented by general formula (II): ##STR195## asthe main component is used as the hole transporting layer. An organicelectroluminescence device having a still higher efficiency of lightemission can be obtained by using this layer.

In general formula (II), X represents a single bond, methylene group,phenylene group, biphenylene group, --O--, --S--, or a group representedby any of: ##STR196## The positions in phenylene group or biphenylenegroup through which the phenylene group or the biphenylene group isbonded to the adjacent aromatic rings are not particularly limited. Itis preferred that the phenylene group and the biphenylene group are1,4-phenylene group and 4,4'-biphenylene group, respectively. Ar⁶ toAr¹⁰ represent each an aryl group having 6 to 18 core carbon atoms,preferably an aryl group having 6 to 18 carbon atoms, which isunsubstituted or substituted with an alkyl group, an alkoxy group, vinylgroup, or styryl group, i.e., the same aryl group as that represented byAr¹ to Ar⁵. Ar⁶ to Ar¹⁰ may be the same with each other or differentfrom each other.

Specific examples of the compound represented by general formula (II)are shown in Table 2.

                  TABLE 2-1A                                                      ______________________________________                                        compound                                                                             X       Ar.sup.6        Ar.sup.7                                       ______________________________________                                          HT-1 --                                                                                                      #STR197##                                                                     #STR198##                                       - HT-2 --                                                                                                   #STR199##                                                                     #STR200##                                       - HT-3 --                                                                                                   #STR201##                                                                     #STR202##                                       - HT-4 --                                                                                                   #STR203##                                                                     #STR204##                                       - HT-5 --                                                                                                   #STR205##                                                                     #STR206##                                       - HT-6 --                                                                                                   #STR207##                                                                     #STR208##                                       - HT-7 --                                                                                                   #STR209##                                                                     #STR210##                                       - HT-8 --                                                                                                   #STR211##                                                                    ##STR212##                                    ______________________________________                                    

                  TABLE 2-1B                                                      ______________________________________                                        compound  Ar.sup.8        Ar.sup.9                                            ______________________________________                                          HT-1                                                                                                    #STR213##                                                                     #STR214##                                            - HT-2                                                                                                 #STR215##                                                                     #STR216##                                            - HT-3                                                                                                 #STR217##                                                                     #STR218##                                            - HT-4                                                                                                 #STR219##                                                                     #STR220##                                            - HT-5                                                                                                 #STR221##                                                                     #STR222##                                            - HT-6                                                                                                 #STR223##                                                                     #STR224##                                            - HT-7                                                                                                 #STR225##                                                                     #STR226##                                            - HT-8                                                                                                 #STR227##                                                                    ##STR228##                                         ______________________________________                                    

                  TABLE 2-2A                                                      ______________________________________                                        com-                                                                            pound X Ar.sup.6 Ar.sup.7                                                   ______________________________________                                          HT-9 --                                                                                                       #STR229##                                                                     #STR230##                                      - HT-10 --                                                                                                   #STR231##                                                                     #STR232##                                      - HT-11 --                                                                                                   #STR233##                                                                     #STR234##                                      - HT-12 --                                                                                                   #STR235##                                                                     #STR236##                                      - HT-13 --                                                                                                   #STR237##                                                                     #STR238##                                      - HT-14 --                                                                                                   #STR239##                                                                     #STR240##                                      - HT-15 --                                                                                                   #STR241##                                                                     #STR242##                                      - HT-16 --                                                                                                   #STR243##                                                                    ##STR244##                                   ______________________________________                                    

                  TABLE 2-2B                                                      ______________________________________                                        compound                                                                              Ar.sup.8            Ar.sup.9                                          ______________________________________                                          HT-9                                                                                                      #STR245##                                                                     #STR246##                                          - HT-10                                                                                                  #STR247##                                                                     #STR248##                                          - HT-11                                                                                                  #STR249##                                                                     #STR250##                                          - HT-12                                                                                                  #STR251##                                                                     #STR252##                                          - HT-13                                                                                                  #STR253##                                                                     #STR254##                                          - HT-14                                                                                                  #STR255##                                                                     #STR256##                                          - HT-15                                                                                                  #STR257##                                                                     #STR258##                                          - HT-16                                                                                                  #STR259##                                                                    ##STR260##                                       ______________________________________                                    

                  TABLE 2-3A                                                      ______________________________________                                        com-                                                                            pound X Ar.sup.6 Ar.sup.7                                                   ______________________________________                                          HT-17 --                                                                                                   #STR261##                                                                     #STR262##                                         - HT-18 --                                                                                                #STR263##                                                                     #STR264##                                         - HT-19 --                                                                                                #STR265##                                                                     #STR266##                                         - HT-20 --                                                                                                #STR267##                                                                     #STR268##                                         - HT-21 --                                                                                                #STR269##                                                                     #STR270##                                         - HT-22 --                                                                                                #STR271##                                                                     #STR272##                                         - HT-23 --                                                                                                #STR273##                                                                     #STR274##                                         - HT-24 --                                                                                                #STR275##                                                                    ##STR276##                                      ______________________________________                                    

                  TABLE 2-3B                                                      ______________________________________                                        compound                                                                              Ar.sup.8         Ar.sup.9                                             ______________________________________                                          HT-17                                                                                                  #STR277##                                                                     #STR278##                                             - HT-18                                                                                               #STR279##                                                                     #STR280##                                             - HT-19                                                                                               #STR281##                                                                     #STR282##                                             - HT-20                                                                                               #STR283##                                                                     #STR284##                                             - HT-21                                                                                               #STR285##                                                                     #STR286##                                             - HT-22                                                                                               #STR287##                                                                     #STR288##                                             - HT-23                                                                                               #STR289##                                                                     #STR290##                                             - HT-24                                                                                               #STR291##                                                                    ##STR292##                                          ______________________________________                                    

                                      TABLE 2-4A                                  __________________________________________________________________________    compound                                                                           X  Ar.sup.6           Ar.sup.7                                           __________________________________________________________________________      HT-25 --                                                                                                 #STR293##                                                                     #STR294##                                           - HT-26 --                                                                                              #STR295##                                                                     #STR296##                                           - HT-27 --                                                                                              #STR297##                                                                     #STR298##                                           - HT-28 --                                                                                              #STR299##                                                                     #STR300##                                           - HT-29 --                                                                                              #STR301##                                                                     #STR302##                                           - HT-30 --                                                                                              #STR303##                                                                     #STR304##                                           - HT-31 --                                                                                              #STR305##                                                                    ##STR306##                                        __________________________________________________________________________

                                      TABLE 2-4B                                  __________________________________________________________________________    compound                                                                             Ar.sup.8           Ar.sup.9                                            __________________________________________________________________________      HT-25                                                                                                   #STR307##                                                                     #STR308##                                            - HT-26                                                                                                #STR309##                                                                     #STR310##                                            - HT-27                                                                                                #STR311##                                                                     #STR312##                                            - HT-28                                                                                                #STR313##                                                                     #STR314##                                            - HT-29                                                                                                #STR315##                                                                     #STR316##                                            - HT-30                                                                                                #STR317##                                                                     #STR318##                                            - HT-31                                                                                                #STR319##                                                                    ##STR320##                                         __________________________________________________________________________

                                      TABLE 2-5A                                  __________________________________________________________________________    compound                                                                           X          Ar.sup.6        Ar.sup.7                                      __________________________________________________________________________      HT-32 --                                                                                                      #STR321##                                                                     #STR322##                                      - HT-33 --                                                                                                   #STR323##                                                                     #STR324##                                      - HT-34                                                                                                      #STR325##                                                                     #STR326##                                                                     #STR327##                                      - HT-35                                                                                                      #STR328##                                                                     #STR329##                                                                     #STR330##                                      - HT-36 --CH.sub.2 --                                                                                        #STR331##                                                                     #STR332##                                      - HT-37 --O--                                                                                                #STR333##                                                                     #STR334##                                      - HT-38 --S--                                                                                                #STR335##                                                                    ##STR336##                                   __________________________________________________________________________

                                      TABLE 2-5B                                  __________________________________________________________________________    compound                                                                           Ar.sup.8        Ar.sup.9                                                 __________________________________________________________________________      HT-32                                                                                              #STR337##                                                                     #STR338##                                                 - HT-33                                                                                           #STR339##                                                                     #STR340##                                                 - HT-34                                                                                           #STR341##                                                                     #STR342##                                                 - HT-35                                                                                           #STR343##                                                                     #STR344##                                                 - HT-36                                                                                           #STR345##                                                                     #STR346##                                                 - HT-37                                                                                           #STR347##                                                                     #STR348##                                                 - HT-38                                                                                           #STR349##                                                                    ##STR350##                                              __________________________________________________________________________

                                      TABLE 2-6A                                  __________________________________________________________________________    compound                                                                           X                    Ar.sup.6        Ar.sup.7                            __________________________________________________________________________      HT-39                                                                                                                   #STR351##                                                                     #STR352##                                                                     #STR353##                            - HT-40                                                                                                                #STR354##                                                                     #STR355##                                                                     #STR356##                            - HT-41                                                                                                                #STR357##                                                                     #STR358##                                                                     #STR359##                            - HT-42                                                                                                                #STR360##                                                                     #STR361##                                                                     #STR362##                            - HT-43                                                                                                                #STR363##                                                                     #STR364##                                                                     #STR365##                            - HT-44                                                                                                                #STR366##                                                                     #STR367##                                                                     #STR368##                            - HT-45                                                                                                                #STR369##                                                                     #STR370##                                                                    ##STR371##                         __________________________________________________________________________

                                      TABLE 2-6B                                  __________________________________________________________________________    compound                                                                           Ar.sup.8        Ar.sup.9                                                 __________________________________________________________________________      HT-39                                                                                              #STR372##                                                                     #STR373##                                                 - HT-40                                                                                           #STR374##                                                                     #STR375##                                                 - HT-41                                                                                           #STR376##                                                                     #STR377##                                                 - HT-42                                                                                           #STR378##                                                                     #STR379##                                                 - HT-43                                                                                           #STR380##                                                                     #STR381##                                                 - HT-44                                                                                           #STR382##                                                                     #STR383##                                                 - HT-45                                                                                           #STR384##                                                                    ##STR385##                                              __________________________________________________________________________

In the organic electroluminescence device of the present invention, thehole transporting layer may contain a single type or a combination of aplurality of types of the above compound. The thickness of the holetransporting layer is generally selected in the range of 5 nm to 5 μm.

In the organic electroluminescence device of the present invention, thelight emitting zone means a zone in which a molecule showingluminescence in the solid state is brought into an excited state bydirectly or indirectly receiving the energy generated by recombinationof holes and electrons and emits light.

The molecule showing luminescence in the solid state is not particularlylimited, and a light emitting material generally used for organicelectroluminescence devices can be used. As the light emitting material,a material having an excellent film-forming property, for example, aluminescent brightening agent, such as a luminescent brightening agentof a condensed polycyclic aromatic compound, a benzoxazole luminescentbrightening agent, a benzothiazole luminescent brightening agent, and abenzimidazole luminescent brightening agent; a metal-chelated oxanoidcompound; or a distyrylbenzene compound can be used. Examples of thecondensed polycyclic aromatic compound include condensed ring lightemitting substances having a skeleton of anthracene, naphthalene,phenanthrene, pyrene, chrysene, or perylene.

As the above luminescent brightening agent, such as a benzoxazoleluminescent brightening agent, a benzothiazole luminescent brighteningagent, and a benzimidazole luminescent brightening agent, theluminescent brightening agents described in the specification ofJapanese Patent Application Laid-Open No. Showa 59(1984)-194393 can beused. Representative examples of such luminescent brightening agentinclude benzoxazole luminescent brightening agents, such as2,5-bis(5,7-di-t-pentyl-2-benzoxazolyl)-1,3,4-thiadiazole,4,4'-bis(5,7-t-pentyl-2-benzoxazolyl)stilbene,4,4'-bis(5,7-di-(2-methyl-2-butyl)-2-benzoxazolyl)stilbene,2,5-bis(5,7-di-t-pentyl-2-benzoxazolyl)thiophene,2,5-bis(5-(α,α-dimethylbenzyl)-2-benzoxazolyl)thiophene,2,5-bis(5,7-di(2-methyl-2-butyl)-2-benzoxazolyl)-3,4-diphenylthiophene,2,5-bis(5-methyl-2-benzoxazolyl)thiophene,4,4'-bis(2-benzoxazolyl)biphenyl,5-methyl-2-(2-(4-(5-methyl-2-benzoxazolyl)phenyl)vinyl)benzoxazole, and2-(2-(4-chlorophenyl)vinyl)naphtho(1,2-d)oxazole; benzothiazoleluminescent brightening agents, such as2,2'-(p-phenylenedivinylene)-bisbenzothiazole; and benzimidazoleluminescent brightening agents, such as2-(2-(4-(2-benzimidazolyl)phenyl)vinyl)-benzimidazole and2-(2-(4-carboxyphenyl)vinyl)benzimidazole. Examples of other compounduseful as the light emitting material include the compounds described in"Chemistry of Synthetic Dyes" Pages 628 to 637 and 640 (1971).

As the above metal-chelated oxanoid compound, for example, compoundsdescribed in the specification of Japanese Patent Application Laid-OpenNo. Showa 63(1988)-295695 can be used. Representative examples of suchcompounds include metal complexes of 8-hydroxyquinoline, such astris(8-quinolinol)aluminum, bis(8-quinolinol)magnesium,bis(benzo(f)-8-quinolinol)zinc, bis(2-methyl-8-quinolinolato)aluminumoxide, tris(8-quinolinol)indium, tris(5-methyl-8-quinolinol)aluminum,8-quinolinollithium, tris(5-chloro-8-quinolinol)gallium,bis(5-chloro-8-quinolinol)calcium, andpoly(zinc(II)-bis(8-hydroxy-5-quinolinonyl)methane); and dilithiumepindridione.

Metal-chelated oxanoid compounds doped with a polycyclic aromaticcompound which are described in the specifications of the U.S. Pat. No.5,141,671 and the U.S. Pat. No. 5,150,006 can also be used. Specificexamples of such compounds include metal chelated complexes of8-hydroxyquinoline, such asbis(2-methyl-8-quinolinolato)(phenolato)aluminum(III),bis(2-methyl-8-quinolinolato)(cresolato)aluminum(III),bis(2-methyl-8-quinolinolato)(phenylphenolato)aluminum(III),bis(2-methyl-8-quinolinolato)(naphtholato)aluminum(III), andbis(2-methyl-8-quinilinolato)aluminum(III)-μ-oxo-bis(2-methyl-8-quinolinolato)aluminum(III),doped with a polycyclic aromatic compound, such as perylene anddibenzoperylene.

As the light emitting compound, other compounds, such as distyrylbenzenederivative described in the specification of European Patent No.0373582, dimethylidene derivatives described in the specification ofEuropean Paten No. 0388768, coumarine derivatives described in thespecification of Japanese Patent Application Laid-Open No. Heisei2(1990)-191694, distyrylpyrazine derivatives described in thespecification of Japanese Patent Application Laid-Open No. Heisei2(1990)-252793, perylene derivatives described in the specification ofJapanese Patent Application Laid-Open No. Heisei 2(1990)-196885,naphthalene derivatives described in the specification of JapanesePatent Application Laid-Open No. Heisei 2(1990)-255789, phthaloperynonederivatives described in the specifications of Japanese PatentApplication Laid-Open No. Heisei 2(1990)-289676 and Japanese PatentApplication Laid-Open No. Heisei 2(1990)-88689, styrylamine derivativesdescribed in the specification of Japanese Patent Application Laid-OpenNo. Heisei 2(1990)-250292, cyclopentadiene derivatives described in thespecification of Japanese Patent Application Laid-Open No. Heisei2(1990)-289675, and polyphenyl compounds described in the specificationof European Patent No. 387715, can be selected and used in accordancewith the color of the light which is desired to be emitted and otherproperties.

The layer of the light emitting zone comprising the above organiccompound may have a laminate structure having two or more layers wheredesired or may be formed by additionally using a fluorescent substanceor a polycyclic aromatic compound in such a manner as that described inthe specifications of the U.S. Pat. No. 4,769,292 and the U.S. Pat. No.5,141,671. In this case, the above organic compound has a form of alayer of a thin film and exhibits the function of injection and a partof the function of light emission which are the functions of the lightemitting zone. The fluorescent substance is present in the thin film ofthe organic compound in a small amount (several percent by mol or less)and exhibits a part of the function of light emission by emitting lightin response with the recombination of electrons and holes.

The layer of the light emitting zone may be constituted with a singlelayer comprising one or more types of the light emitting material or alaminate of layers of different light emitting materials.

In the organic luminescence device of the present invention, otherlayers may be formed between the anode and the cathode in addition tothe layer of the hole transporting zone and the layer of the lightemitting zone which are described above, where necessary, for example,to increase the efficiency of injection of electrons from the cathode orto improve the adhesion of a layer to the anode.

In the following, preferable examples of preparation of the organicelectroluminescent device of the present invention are described. Atfist, a thin film comprising a desired electrode material, such as amaterial for the anode, is formed on a suitable substrate to a thicknessof 500 nm or less, preferably in the range of 10 to 20 nm, by a method,such as the vapor deposition and the sputtering, to prepare an anode. Onthe prepared anode, thin films comprising materials constituting thedevice, i. e., materials for the hole injecting layer, the holetransporting layer, and the layer of light emitting zone, are formed.

As the method of forming the thin films, the spin-coating, the casting,or the vapor deposition can be used. The vacuum vapor deposition ispreferable because a uniform film is easily obtained, and the formationof pin-holes can be prevented more easily. The condition of the vacuumvapor deposition is different depending on the type of the used compoundas well as the crystal structure and the association structure which aredesired to be formed in the molecular deposition film. In general, it ispreferred that the conditions are selected in the following range: atemperature of a heated boat of 50 to 400° C., a vacuum of 10⁻⁶ to 10⁻³Pa, a rate of vapor deposition of 0.01 to 50 nm/sec, a substratetemperature of -50 to 300° C., and a film thickness of 5 nm to 5 μm.

After these layers have been formed, a thin film comprising a cathodematerial is formed on the formed layers by a method, such as the vapordeposition or the sputtering, to a thickness of 500 nm or less,preferably in the range of 10 to 200 nm, to form a cathode. Thus, thedesired electroluminescence device can be prepared. For the preparationof the electroluminescence device, the procedures for the preparationmay be conducted in the reversed order.

The electroluminescence device of the present invention which can beprepared as described above emits light by applying a direct voltage of3 to 40 V in the condition that the anode is connected to a positiveelectrode (+) and the cathode is connected to a negative electrode (-).When the connection is reversed, no electric current is observed and nolight is emitted at all. When an alternating voltage is applied to theelectroluminescence device, light emission is observed only in thecondition that the polarity of the anode is positive and the polarity ofthe cathode is negative. When an alternating voltage is applied to theorganic EL device, any type of wave shape can be used.

It is preferred that the device of the present invention is supported ona support. The support is not particularly limited, and a supportconventionally used in organic electroluminescence devices, such asglass, a transparent plastic, and quartz, can be used.

The present invention also provides an organic thin film comprising twolayers which are a layer containing a compound represented by generalformula (I) and having a thickness of 5 nm to 5 μm and a layercontaining a compound represented by general formula (II) and having athickness of 5 nm to 5 μm. This organic thin film has very excellenthole injecting and transporting properties and can advantageously beused for organic electroluminescence devices. This organic thin film canalso be used widely for other organic devices and photosensitive filmsin the electronic photography.

This organic thin film can be prepared by the same process as that usedfor preparation of the hole injection layer and the hole transportinglayer in the preparation of the above organic electroluminescencedevice.

In the following, the novel triamine compound which is another object ofthe present invention is described. The triamine compound of the presentinvention is a compound having a structure represented by generalformula (III): ##STR386## [wherein Ar¹ to Ar⁴ represent each an arylgroup having 6 to 18 core carbon atoms which is unsubstituted orsubstituted with an alkyl group, an alkoxy group, vinyl group, or styrylgroup and may be the same with each other or different from each other,and Ar⁵ represents biphenyl group which is unsubstituted orsubstituted].

In above general formula (III), Ar⁵ preferably represents an aryl grouprepresented by: ##STR387## [wherein R represents hydrogen, an alkylgroup having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbonatoms, or phenyl group; n represents an integer of 0 to 5; and when aplurality of R are present, the plurality of R may be the same with eachother or different from each other], and Ar¹ to Ar⁴ represent each anaryl group represented by any of the general formulae: ##STR388##

R¹ to R⁵ in the above formulae represent each hydrogen, an alkyl grouphaving 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms,or phenyl group. m represents an integer of 0 to 5, p represents aninteger of 0 to 4, q represents an integer of 0 to 5, x represents aninteger of 0 to 3, and y represents an integer of 0 to 4. When aplurality of R¹, R², R³, R⁴, or R⁵ are present, the plurality of R¹, R²,R³, R⁴, or R⁵ be the same with each other or different from each other.Ar¹ to Ar⁴ may be the same with each other or different from each other.R represents hydrogen, an alkyl group having 1 to 6 carbon atoms, analkoxy group having 1 to 6 carbon atoms, or phenyl group; n representsan integer of 0 to 5; and when a plurality of R are present, theplurality of R may be the same with each other or different from eachother.

The alkyl group having 1 to 6 carbon atoms which is represented by anyof R¹ to R⁵ and R may be linear, branched, or cyclic. Specific examplesof the alkyl group having 1 to 6 carbon atoms include methyl group,ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutylgroup, sec-butyl group, tert-butyl group, n-pentyl group, isopentylgroup, n-hexyl group, isohexyl group, cyclopropyl group, cyclobutylgroup, cyclopentyl group, and cyclohexyl group. The alkoxy group having1 to 6 carbon atoms which is represented by any of R¹ to R⁵ and R may belinear, branched, or cyclic. Specific examples of the alkoxy grouphaving 1 to 6 carbon atoms include methoxy group, ethoxy group,n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group,sec-butoxy group, tert-butoxy group, n-pentoxy group, isopentoxy group,n-hexoxy group, isohexoxy group, cyclopropoxy group, cyclobutoxy group,cyclopentoxy group, and cyclohexoxy group.

Examples of the above triamine compound represented by general formula(III) include the following compounds: ##STR389##

In the above formulae, the abbreviations represent groups as follows:Me: methyl group, Et: ethyl group, nPr: n-propyl group, iPr: isopropylgroup, nBu: n-butyl group, sBu: sec-butyl group, tBu: tert-butyl group,nPe: n-pentyl group, and nHex: n-hexyl group.

The present invention is described in more detail with reference toexamples. However, the present invention is not limited by the examples.

EXAMPLE 1

Preparation of HI-3

(1) Into a 500 ml three-necked flask, 16.5 g of aniline (a product ofHIROSHIMA WAKO Co., Ltd.), 50 g of p-fluoronitrobenzene (a product ofHIROSHIMA WAKO Co., Ltd.), 1 g of copper powder, 48.9 g anhydrouspotassium carbonate, and 330 ml of DMF (dimethylformamide) were placed,and the reaction was allowed to proceed in the resultant mixture at 150°C. for 8 hours.

After the reaction had been completed, the reaction mixture was cooled,and salts were removed from the reaction mixture by filtration. Theobtained filtrate was poured into 3 liters of water, and the formedcrystal in an amount of 40 g was separated by filtration. The separatedcrystal was dissolved into 600 ml of DMF. To the resultant solution, 8 gof a 5% Pd--C was added, and the hydrogenation was conducted under anatmospheric pressure for 4 hours by bubbling hydrogen gas through thereaction mixture.

After the reaction had been completed, the Pd--C was removed from thereaction mixture by filtration. The obtained filtrate was poured into 4liters of water, and the precipitated crystal was separated byfiltration to obtain 28 g of 4,4'-diamino-triphenylamine.

(2) Into a 300 ml three-necked flask, 1.0 g of4,4'-diamino-triphenylamine obtained above in (1), 4.0 g of3-iodotoluene (a product of TOKYO KASEI Co., Ltd.), 3 g of anhydrouspotassium carbonate, and 1 g of copper powder (a product of HIROSHIMAWAKO Co., Ltd.) were placed and then dissolved in 200 ml ofdimethylsulfoxide (DMSO). The reaction was allowed to proceed in theobtained mixture at 200° C. for 8 hours while the mixture was stirred.

After the reaction had been completed, the reaction mixture wasfiltered, and the obtained filtrate was extracted with methylenechloride. From the obtained extract, the solvent was removed by using arotary evaporator, and the residual product was purified by using acolumn packed with silica-gel (a product of HIROSHIMA WAKO Co., Ltd.)with toluene as the developing solvent to obtain 0.78 g of a lightyellow powder.

This product was identified as4,4'-bis[N,N-di(3-tolyl)amino]-triphenylamine (HI-3) by the measurementsof NMR and FD-MS (field diffusion mass spectrum).

EXAMPLE 2

Preparation of HI-16

The reactions and the purifications were conducted in accordance withthe same procedures as those conducted in Example 1 except that 4.0 g of4-iodoanisol (a product of HIROSHIMA WAKO Co., Ltd.) was used in placeof 3-iodotoluene used in Example 1 (2), and 0.66 g of a light yellowpowder was obtained.

This product was identified as4,4'-bis[N,N-di(4-methoxyphenyl)amino]triphenylamine (HI-16) by themeasurements of NMR and FD-MS.

EXAMPLE 3

Preparation of HI-35

(1) Into a 500 ml three-necked flask, 75 g of biphenyl (a product ofHIROSHIMA WAKO Co., Ltd.), 19.2 g of ortho-periodic acid (a product ofHIROSHIMA WAKO Co., Ltd.), 64.3 g of iodine, 230 ml of acetic acid, and7.6 ml of concentrated sulfuric acid were placed, and the reaction wasallowed to proceed in the resultant mixture at 70° C. for 2 hours.

After the reaction had been finished, the reaction mixture was cooledand then poured into 1 liter of methanol while methanol was stirred. Theprecipitated crystal was separated by filtration and then recrystallizedby using 2 liters of acetonitrile to obtain 7.2 g of 4-iodobiphenyl.

(2) Then, the reactions and the purifications were conducted inaccordance with the same procedures as those conducted in Example 1except that 5.0 g of 4-iodobiphenyl obtained above in (1) was used inplace of 3-iodotoluene used in Example 1 (2), and 0.34 g of a lightyellow powder was obtained.

This product was identified as4,4''-bis[N,N-di(dipheno-4-yl)amino]triphenylamine (HI-35) by themeasurements of NMR and FD-MS.

Preparation Example 1

Preparation of HT-23

The reactions and the purifications were conducted in accordance withthe same procedures as those conducted in Example 1 except that 2.0 g ofN,N'-diphenyl-4,4'-benzidine was used in place of4,4'-diamino-triphenylamine used in Example 1 (2), and 1.6 g of a whitepowder was obtained.

This product was identified asN,N'-bis(3-tolyl)-N,N'-diphenyl-4,4'-benzidine (HT-23) by themeasurements of NMR and FD-MS.

Preparation Example 2

Preparation of HT-39

(1) A mixture of 20 g of 4-iodobiphenyl obtained above in Example 3 (1)and 150 ml of acetic acid was heated to 80° C., and 40 ml of fumingnitric acid was added dropwise to the heated mixture at 75 to 90° C.during 2 hours. After the resultant mixture was kept being stirred for 1hour at this temperature, the mixture was cooled to 50° C., and 200 mlof methanol was added to the cooled mixture to obtain 11 g of a lightyellow crystal after filtration.

The obtained product was heated with a mixture of 1.6 g of aniline (aproduct of HIROSHIMA WAKO Co., Ltd.), 100 ml of nitrobenzene, 1 g ofcopper powder, and 10 g of anhydrous potassium carbonate at 200° C., andthe reaction was allowed to proceed for 48 hours. The insoluble portionwas then removed from the reaction product by filtration. After thesolvent was removed from the filtrate by the vacuum distillation, theresidual product was recrystallized by using 200 ml of ethanol to obtain8 g of a crystal.

The obtained crystal was dissolved in 200 ml of DMF. To the resultantsolution, 2 g of a 5% Pd--C was added, and the hydrogenation wasconducted under an atmospheric pressure for 4 hours by bubbling hydrogengas through the reaction mixture.

The insoluble portion was removed from the reaction product byfiltration, and the obtained filtrate was poured into 1 liter of watersaturated with sodium chloride. The precipitated crystal was separatedby filtration and reprecipitated by using 500 ml of toluene to obtain 5g of 4,4'-bis(4-aminophenyl)triphenylamine.

(2) The reactions and the purifications were conducted in accordancewith the same procedures as those conducted in Example 1 (2) except that1.0 g of 4,4'-bis(4-aminophenyl)triphenylamine obtained above in (1) wasused in place of 4,4'-diamino-triphenylamine used in Example 1 (2), and3.0 g of iodobenzene (a product of HIROSHIMA WAKO Co., Ltd.) was used inplace of 3-iodotoluene used in Example 1 (2), and 0.31 g of a whitepowder was obtained.

This product was identified as4,4'-bis[4-(N,N-diphenylamino)phenyl]triphenylamine (HT-39) by themeasurements of NMR and FD-MS.

Preparation Example 3

Preparation of DPVBi

(1) To 150 ml of carbon tetrachloride, 10 g of 4,4'-dimethylbiphenyl (aproduct of ALDRICH Co.), 20 g of N-bromosuccinimide (a product ofHIROSHIMA WAKO Co., Ltd.), and 0.9 g of benzoyl peroxide (a product ofHIROSHIMA WAKO Co., Ltd.) were added, and the reaction was allowed toproceed in the resultant mixture at 90° C. for 2 hours while the mixturewas stirred.

After the reaction product was cooled, the precipitated crystal waswashed with 100 ml of methanol to obtain 13.2 g of4,4'-dibromomethyl-biphenyl.

(2) Into a 300 ml three-necked flask, 1.0 g of4,4'-dibromomethyl-biphenyl obtained above in (1), 3.0 g of benzophenone(a product of TOKYO KASEI Co., Ltd.), and 0.50 g of potassium t-butoxide(a product of HIROSHIMA WAKO Co., Ltd.) were placed and then dissolvedin 150 ml of DMSO. The reaction was allowed to proceed in the resultantsolution at a room temperature for 2 hours while the solution wasstirred.

After the reaction had been completed, the reaction solution wasextracted with toluene, and then the solvent was removed from theextract by distillation using a rotary evaporator. The residual productwas purified by using a column packed with silica-gel (a product ofHIROSHIMA WAKO Co., Ltd.) with toluene as the developing solvent toobtain 1.1 g of a white powder.

This product was identified as4,4'-bis(2,2-diphenyl-1-vinyl)-1,1'-biphenyl (DPVBi) by the measurementsof NMR and FD-MS.

Preparation Example 4

Preparation of MTDATA

The reactions and the purifications were conducted in accordance withthe same procedures as those conducted in Example 1 (2) except that 1.0g of 4,4',4"-triiodotriphenylamine was used in place of 3-iodotolueneused in Example 1 (2), and 1.0 g of N-(3-tolyl)-N-phenylamine (a productof ALDRICH Co.) was used in place of 4,4'-diaminotriphenylamine used inExample 1 (2), and 0.30 g of a light yellow powder was obtained.

This product was identified as4,4',4"-tris[N-(3-tolyl)-N-phenylamino]triphenylamine (MTDATA) by themeasurements of NMR and FD-MS.

Preparation Example 5

Preparation of TA-1

Into a 300 ml three-necked flask, 2.0 g ofN,N'-diphenyl-1,4-phenylenediamine (a product of KANTO KAGAKU Co.,Ltd.), 50 ml of 4-fluoronitrobenzene (a product of HIROSHIMA WAKO Co.,Ltd.), 5 g of anhydrous potassium carbonate, and 1 g of copper powderwere placed, and the reaction was allowed to proceed in the resultantmixture at 200° C. for 8 hours while the mixture was stirred.

After the reaction had been completed, the reaction mixture wasfiltered. The obtained filtrate was extracted with methylene chloride,and the solvent was removed from the obtained extract by distillation.The residual product was purified by using a column packed withsilica-gel (a product of HIROSHIMA WAKO Co., Ltd.) with toluene as thedeveloping solvent.

The obtained product was dissolved in 100 ml of dimethylformamide (DMF).To the resultant solution, 10 g of a 5% by weight Pd--C was added, andthe reaction was allowed to proceed in the resultant mixture for 8 hoursunder a hydrogen stream. The reaction mixture was filtered, and thesolvent was removed from the obtained filtrate. The residual product wasdissolved in 100 ml of iodobenzene (a product of HIROSHIMA WAKO Co.,Ltd.). To the obtained solution, 10 g of anhydrous potassium carbonateand 1 g of copper powder were added, and the reaction was allowed toproceed in the resultant mixture at 200° C. for 8 hours.

After the reaction had been completed, the reaction mixture wasfiltered. The obtained filtrate was extracted with methylene chloride,and the solvent was removed from the obtained extract by using a rotaryevaporator. The residual product was purified by using a column packedwith silica-gel with toluene as the developing solvent to obtain 0.24 gof a yellow powder.

This product was identified asN,N'-bis[4-(N,N-diphenylamino)phenyl]-N,N'-diphenyl-1,4-phenylenediamine(TA-1) by the measurements of NMR and FD-MS.

EXAMPLE 4

On a glass substrate having the size of 25 mm×75 mm×1.1 mm, an ITOelectrode was formed to the thickness of 100 nm, and the obtainedproduct was used as the transparent substrate. The prepared transparentsubstrate was cleaned with isopropyl alcohol for 5 minutes by usingultrasonic wave, with pure water for 5 minutes, and finally withisopropyl alcohol for 5 minutes by using ultrasonic wave.

The cleaned transparent substrate was fixed to a substrate holder of acommercial apparatus for vacuum vapor deposition (a product of NIPPONSHINKU GIJUTU Co., Ltd.). HI-3 obtained in Example 1 was placed into anelectrically heated boat made of molybdenum, and HT-23 obtained inPreparation Example 1 was placed into another electrically heated boatmade of molybdenum. DPVBi obtained in Preparation Example 3 was placedinto still another electrically heated boat made of molybdenum. Thepressure in the vacuum chamber was then reduced to 1×10⁻³ Pa. On thesubstrate, HI-3, HT-23, and DPVBi were successively laminated bydeposition to the thickness of 60 nm, 23 nm, and 40 nm, respectively, byheating the respective boats successively.

The pressure of the apparatus was then adjusted to an atmosphericpressure, and tris(8-hydroxyquinoline)aluminum (Alq, a product of DOJINKAGAKU KENKYUSHO Co., Ltd.) was placed in another electrically heatedboat made of molybdenum. Magnesium ribbon was placed in still anotherelectrically heated boat made of molybdenum, and silver was placed in abasket made of tungsten. After the pressure in the apparatus was reducedto 2×10⁻⁴ Pa, the boat containing Alq was first electrically heated todeposit Alq on DPVBi to the thickness of 20 nm. Then, magnesium andsilver were vaporized in such amounts that the ratio by weight ofmagnesium to silver was 10:1 to form a cathode of an alloy of magnesiumand silver to the thickness of 200 nm. Thus, an organicelectroluminescence device was prepared.

A voltage was applied to the prepared device by connecting the ITOelectrode of the device to a positive electrode (+) and the cathode madeof the magnesium-silver alloy to a negative electrode (-), and thedevice was brought to emit light. The following result was obtained byapplication of the voltage of 8 V: the density of electric current: 1.6mA/cm², the luminance: 30 cd/m², and the efficiency of light emission:0.74 lumen/W. The prepared device showed a high efficiency.

EXAMPLE 5

An organic electroluminescence device was prepared in accordance withthe same procedures as those conducted in Example 4 except that HI-16obtained in Example 2 was used in place of HI-3 used in Example 4.

A voltage was applied to the prepared device by connecting the ITOelectrode of the device to a positive electrode (+) and the cathode madeof the magnesium-silver alloy to a negative electrode (-), and thedevice was brought to emit light. The following result was obtained byapplication of the voltage of 8 V: the density of electric current: 2.0mA/cm², the luminance: 55 cd/m², and the efficiency of light emission:1.1 lumen/W. The prepared device showed a high efficiency.

EXAMPLE 6

An organic electroluminescence device was prepared in accordance withthe same procedures as those conducted in Example 4 except that HI-35obtained in Example 3 was used in place of HI-3 used in Example 4.

A voltage was applied to the prepared device by connecting the ITOelectrode of the device to a positive electrode (+) and the cathode madeof the magnesium-silver alloy to a negative electrode (-), and thedevice was brought to emit light. The following result was obtained byapplication of the voltage of 8 V: the density of electric current: 1.8mA/cm², the luminance: 40 cd/m², and the efficiency of light emission:0.87 lumen/W. The prepared device showed a high efficiency.

EXAMPLE 7

An organic electroluminescence device was prepared in accordance withthe same procedures as those conducted in Example 4 except that HT-39obtained in Preparation Example 2 was used in place of HT-23 used inExample 4.

A voltage was applied to the prepared device by connecting the ITOelectrode of the device to a positive electrode (+) and the cathode madeof the magnesium-silver alloy to a negative electrode (-), and thedevice was brought to emit light. The following result was obtained byapplication of the voltage of 8 V: the density of electric current: 2.14 mA/cm², the luminance: 38 cd/m², and the efficiency of light emission:0.71 lumen/W. The prepared device showed a high efficiency.

Comparative Example 1

An organic electroluminescence device was prepared in accordance withthe same procedures as those conducted in Example 4 except that MTDATAobtained in Preparation Example 4 was used in place of HI-3 used inExample 4.

A voltage was applied to the prepared device by connecting the ITOelectrode of the device to a positive electrode (+) and the cathode madeof the magnesium-silver alloy to a negative electrode (-), and thedevice was brought to emit light. The following result was obtained byapplication of the voltage of 8 V: the density of electric current: 2.1mA/cm², the luminance: 20 cd/m², and the efficiency of light emission:0.37 lumen/W. The prepared device showed a low efficiency. ##STR390##

Comparative Example 2

An organic electroluminescence device was prepared in accordance withthe same procedures as those conducted in Example 4 except that HT-23was not laminated.

A voltage was applied to the prepared device by connecting the ITOelectrode of the prepared device to a positive electrode (+) and thecathode made of the magnesium-silver alloy to a negative electrode (-),and the device was brought to emit light. The following result wasobtained by application of the voltage of 8 V: the density of electriccurrent: 7.0 mA/cm², the luminance: 6.0 cd/m², and the efficiency oflight emission: 0.03 lumen/W. The prepared device showed a lowefficiency.

Comparative Example 3

An organic electroluminescence device was prepared in accordance withthe same procedures as those conducted in Example 4 except that TA-1obtained in Preparation Example 5 was used in place of HI-3 used inExample 4.

A voltage was applied to the prepared device by connecting the ITOelectrode of the prepared device to a positive electrode (+) and thecathode made of the magnesium-silver alloy to a negative electrode (-),and the device was brought to emit light, The following result wasobtained by application of the voltage of 8 V: the density of electriccurrent: 1.5 mA/cm², the luminance: 7.0 cd/m², and the efficiency oflight emission: 0.18 lumen/W. The prepared device showed a lowefficiency. ##STR391##

Comparative Example 4

An organic electroluminescence device was prepared in accordance withthe same procedures as those conducted in Example 4 except that BTBIBTwas used in place of HI-3 used in Example 4, and DMOVCH was used inplace of HT-23 used in Example 4.

A voltage was applied to the prepared device by connecting the ITOelectrode of the prepared device to a positive electrode (+) and thecathode made of the magnesium-silver alloy to a negative electrode (-),and the device was brought to emit light. The following result wasobtained by application of the voltage of 8 V: the density of electriccurrent: 1.9 mA/cm², the luminance: 17 cd/m², and the efficiency oflight emission: 0.35 lumen/W. The prepared device showed a lowefficiency. ##STR392##

EXAMPLE 8

On an aluminum substrate, an undercoat layer comprising amethoxymethylated nylon (a product of UNITIKA Co., Ltd.; trade name,T-8) was formed to the thickness of 0.1 μm. On the formed undercoatlayer, a layer for charge generation comprising an A-typetitanylphthalocyanine and polyvinylbutyral (a product of SEKISUI KAGAKUCo., Ltd.; trade name, BX-1) was formed to the thickness of 0.1 μm. Onthe thus formed layer for charge generation, a hole injecting thin filmwas formed by depositing HI-3 obtained in Example 1 and HT-23 obtainedin Preparation Example 1 to the thickness of 60 nm and 20 nm,respectively, by the vacuum vapor deposition in accordance with the sameprocedures as those conducted in Example 4.

The property for the electronic photography of this film was evaluatedby using a testing apparatus for electrostatic recording produced byKAWAGUCHI DENKI Co., Ltd. in the following manner. The film was chargedby corona discharge of -6 kV, and the charge was then attenuated in thedark for 3 seconds. The film was then exposed to white light of 5 luxesfor 5 seconds, and the time (by second) passed before the surfacepotential of the film reached 1/2 of the initial value was obtained. Asthe result, the half-life light exposure was found to be 0.4 lux-second.

As shown in the above, the organic thin film of the present inventionhad a very excellent property for the electronic photography.

As shown in the above results, the organic electroluminescence devicesin Comparative Examples 1 to 4 which had constitutions based on theconventional technology showed efficiencies of light emission as low as0.03 to 0.37 lumen/W. In contrast, as shown in Examples 4 to 7, theorganic electroluminescence devices having the constitution of thepresent invention showed remarkably increased efficiencies of lightemission which were as high as 0.71 to 1.1 lumen/W. As clearly shown inExample 8, the organic thin film of the present invention showedexcellent hole injecting and transporting properties.

EXAMPLE 9

Preparation of Compound (3)

(1) Synthesis of 4,4'-diamino-4"-phenyl-triphenylamine (Compound A)

Into a 500 ml flask of an egg plant shape, 25 g of 4-aminobiphenyl (aproduct of ALDRICH Co.), 62.6 g of 4-fluoronitrobenzene (a product ofHIROSHIMA WAKO Co., Ltd.), 0.94 g of copper powder, 40.8 g of anhydrouspotassium carbonate, and 280 ml of dimethylformamide (DMF; a product ofHIROSHIMA WAKO Co., Ltd.) were placed. The resultant mixture was heatedto 160° C. in an oil bath under an argon stream, and the reaction wasallowed to proceed in this mixture at this temperature for 72 hours.After the reaction had been completed, the insoluble portion was removedfrom the reaction product by filtration, and DMF was removed from thefiltrate by distillation. To the residual product, 1.5 liters ofmethanol was added, and the resultant mixture was stirred under heatingat 60° C. The formed crystal was separated by filtration. After thisprocedure was repeated 4 times, 33.8 g of4,4'-dinitro-4"-phenyl-triphenylamine was obtained.

Into a 1 liter flask of an egg plant shape,4,4'-dinitro-4"-phenyl-triphenylamine obtained above, 500 ml of DMF, and6.8 g of a 5% by weight Pd--C (a product of HIROSHIMA WAKO Co., Ltd.)were placed. Then, hydrogen gas was blown into the obtained mixtureunder an atmospheric pressure to allow the hydrogenation reaction toproceed at a room temperature. After the reaction had been completed,the catalyst was removed from the reaction product by filtration. Theresultant reaction solution was poured into 1.5 liters of water, and theprecipitated crystal was separated by filtration. The obtained crystalwas extracted with 1 liter of ethyl acetate. The obtained extract waswashed with water and dehydrated with anhydrous magnesium sulfate (aproduct of HIROSHIMA WAKO Co., Ltd.), and the solvent was removed fromthe dehydrated extract to obtain 25 g of the compound of the object:4,4'-diamino-4"-phenyl-triphenylamine (Compound A).

(2) Synthesis of Compound (3)

Into a 500 flask of an egg plant shape, 5.01 g of4,4'-diamino-4"-phenyl-triphenylamine (Compound A) obtained above in(1), 25 ml of 3-iodotoluene (a product of HIROSHIMA WAKO Co., Ltd.), 16g of anhydrous potassium carbonate, 6 g of copper powder, and 200 ml ofdimethylsulfoxide (DMSO; a product of HIROSHIMA WAKO Co., Ltd.) wereplaced, and the reaction was allowed to proceed in the resultant mixtureunder an argon stream at 180° C. for 6 hours. After the reaction wascompleted, the insoluble portion was removed from the reaction productby filtration, and the obtained filtrate was extracted with 1 liter ofmethylene chloride. The extract was washed with water and dehydratedwith anhydrous magnesium sulfate, and the solvent was removed from thedehydrated extract. The obtained product was purified by using a columnpacked with activated alumina (a product of HIROSHIMA WAKO Co., Ltd.) toobtain 6.5 g of a light yellow powder.

This product was identified as4,4'-bis[N,N-di-(3-tolyl)amino]-4"-phenyl-triphenylamine by themeasurements of the field diffusion mass spectrum (FD-MS) and the protonnuclear magnetic resonance spectrum (¹ H-NMR). The yield was 63% (basedon Compound A), and the melting point was 180 to 181° C.

The whole chart of the ¹ H-NMR is shown in FIG. 1, and the enlargeddetail of the ¹ H-NMR is shown in FIG. 2.

In the measurement of FD-MS of this compound, the main peak was observedat m/z=711, and this corresponds to C₅₂ H₄₅ N₃ =711.

EXAMPLE 10

Preparation of Compound (20)

The same procedures as those conducted in Example 9 were conductedexcept that 25 ml of 4-iodoanisol (a product of HIROSHIMA WAKO Co.,Ltd.) was used in place of 3-iodotoluene used in Example 9 (2), and 5.75g of 4,4'-bis[N,N-di(4-anisyl)amino]-4"-phenyl-triphenylamine wasobtained. The yield was 52% (based on Compound A), and the melting pointwas 201° C.

The result of the measurement of ¹ H-NMR of this compound is shown inthe following:

DMSO-d₆ : δ7.63˜7.55 (dd, 4H); 7.44˜7.40 (t, 2H), 7.32˜7.28 (t, 1H);7.09˜7.06 (d, 2H); 7.04˜6.94 (dd, 8H); 6.81˜6.40 (dd, 16H); 3.72 (s,12H) ppm.

EXAMPLE 11

Preparation of Compound (36)

The same procedures as those conducted in Example 9 were conductedexcept that 35 g of 4-iodobiphenyl obtained in Example 3 (1) was used inplace of 3-iodotoluene used in Example 9 (2), and 4.65 g of4,4'-bis[N,N-di-(biphenyl)amino]-4"-phenyl-triphenylamine was obtained.The yield was 34% (based on Compound A), and the melting point was 277°C.

The result of the measurement of ¹ H-NMR of this compound is shown inthe following:

DMSO-d₆ : δ7.63˜7.55 (dd, 20H); 7.45˜7.39 (t, 10H), 7.32˜7.27 (t, 5H);7.09˜7.06 (d, 10H); 7.04˜6.94 (dd, 8H) ppm.

EXAMPLE 12

Preparation of Compound (43)

(1) Synthesis of 4,4'-diamino-4"-(4-tolyl)-triphenylamine (Compound B)

A mixture of 100 g of phenyltoluene (a product of ALDRICH Co.) and 1liter of acetic acid was heated to 80° C., and 200 ml of fuming nitricacid was added dropwise to the heated mixture at 75 to 90° C. during 2hours. After the resultant mixture was kept being stirred for 1 hour atthis temperature, the mixture was cooled to 50° C., and 1 liter ofmethanol was added to the cooled mixture to obtain 47 g of a crystal.The obtained crystal was dissolved in 1 liter of DMF. To the resultantsolution, 10 g of a 5% Pd--C was added, and the hydrogenation wasconducted under an atmospheric pressure for 6 hours by bubbling hydrogengas through the reaction mixture.

The insoluble portion was then removed from the reaction mixture byfiltration, and the obtained filtrate was poured into 3 liters of watersaturated with sodium chloride. The precipitated crystal was separatedby filtration and reprecipitated by using 500 ml of toluene to obtain 37g of 4'-methyl-4-aminobiphenyl.

Then, the same procedures as those conducted in Example 9 (1) wereconducted except that 25 g of 4'-methyl-4-aminobiphenyl obtained in theabove was used in place of 4-aminobiphenyl used in Example 9 (1), and 22g of 4,4'-diamino-4"-(4-tolyl)-triphenylamine (Compound B) was obtained.

(2) Synthesis of Compound (43)

The same procedures as those conducted in Example 9 (2) were conductedexcept that 5.00 g of Compound B was used in place of Compound A used inExample 9 (2), and 25 ml of iodobenzene (a product of HIROSHIMA WAKOCo., Ltd.) was used in place of 3-iodotoluene used in Example 9 (2), and6.24 g of 4,4'-bis(N,N-diphenylamino)-4"-(4-tolyl)triphenylamine wasobtained. The yield was 68% (based on Compound B), and the melting pointwas 171° C.

The result of the measurement of ¹ H-NMR of this compound is shown inthe following:

DMSO-d₆ : δ7.63˜7.55 (dd, 4H); 7.53˜6.81 (m, 20H), 7.11˜7.03 (dd, 4H);7.04˜6.94 (dd, 8H); 2.28 (s, 3H) ppm.

EXAMPLE 13

Preparation of Compound (57)

(1) Synthesis of 4,4'-diamino-4"-(4-anisyl)-triphenylamine (Compound C)

A mixture of 100 g of 4-phenylanisole (a product of ALDRICH Co.) and 1liter of acetic acid was heated to 80° C., and 200 ml of fuming nitricacid was added dropwise to the heated mixture at 75 to 90° C. during 2hours. After the resultant mixture was kept being stirred for 1 hour atthis temperature, the mixture was cooled to 50° C., and 1 liter ofmethanol was added to the cooled mixture to obtain 51 g of a crystal.

The obtained crystal was dissolved in 1 liter of DMF. To the resultantsolution, 10 g of a 5% Pd--C was added, and the hydrogenation wasconducted under an atmospheric pressure for 6 hours by bubbling hydrogengas through the reaction mixture.

The insoluble portion was removed from the reaction mixture byfiltration, and the obtained filtrate was poured into 3 liters of watersaturated with sodium chloride. The precipitated crystal was separatedby filtration and reprecipitated by using 500 ml of toluene to obtain 41g of 4'-methoxy-4-aminobiphenyl.

Then, the same procedures as those conducted in Example 9 (1) wereconducted except that 25 g of 4'-methoxy-4-aminobiphenyl obtained in theabove was used in place of 4-aminobiphenyl used in Example 9 (1), and 23g of 4,4'-diamino-4"-(4-anisyl)-triphenylamine (Compound C) wasobtained.

(2) Synthesis of Compound (57)

The same procedures as those conducted in Example 9 (2) were conductedexcept that 5.00 g of Compound C was used in place of Compound A used inExample 9 (2), and 25 ml of iodobenzene was used in place of3-iodotoluene used in Example 9 (2), and 5.58 g of4,4'-bis(N,N-diphenylamino)-4"-(4-anisyl)-triphenylamine was obtained.The yield was 62% (based on Compound C), and the melting point was 177°C.

The result of the measurement of ¹ H-NMR of this compound is shown inthe following:

DMSO-d₆ : δ7.62˜7.55 (dd, 4H); 7.53˜6.80 (m, 20H), 7.12˜7.02 (dd, 4H);7.03˜6.94 (dd, 8H); 3.70 (s, 3H) ppm.

EXAMPLE 14

Preparation of Compound (70)

(1) Synthesis of 4,4'-diamino-4"-biphenyl-triphenylamine (Compound D)

The same procedures as those conducted in Example 9 (1) were conductedexcept that 25 g of 4-aminoterphenyl (a product of TOKYO KASEI Co.,Ltd.) was used in place of 4-aminobiphenyl used in Example 9 (1), and 14g of 4,4'-diamino-4"-biphenyl-triphenylamine (Compound D) was obtained.

(2) Preparation of Compound (70)

The same procedures as those conducted in Example 9 (2) were conductedexcept that 5.00 g of Compound D was used in place of Compound A used inExample 9 (2), and 25 ml of iodobenzene was used in place of3-iodotoluene used in Example 9 (2), and 3.21 g of4,4'-bis(N,N-diphenylamino)-4"-biphenyl-triphenylamine was obtained. Theyield was 38% (based on Compound D), and the melting point was 178° C.

The result of the measurement of ¹ H-NMR of this compound is shown inthe following:

DMSO-d₆ : δ7.62˜7.55 (dd, 4H); 7.52˜6.81 (m, 20H), 7.42˜7.38 (t,2H);7.31˜7.27 (t, 1H); 7.08˜7.00 (dd, 4H); 7.09˜7.06 (dd, 4 H); 7.04˜6.94(dd, 8H) ppm.

EXAMPLE 15

Preparation of an Organic Electroluminescence Device by Using Compound(3)

On a glass substrate having the size of 25 mm×75 mm×1.1 mm, an ITO(indium tin oxides) electrode was formed to the thickness of 100 nm, andthe obtained product was used as the transparent substrate. The preparedtransparent substrate was cleaned with isopropyl alcohol for 5 minutesby using ultrasonic wave, with pure water for 5 minutes, and finallywith isopropyl alcohol for 5 minutes by using ultrasonic wave.

The cleaned transparent substrate was fixed to a substrate holder of acommercial apparatus for vacuum vapor deposition (a product of NIPPONSHINKU GIJUTU Co., Ltd.). Into 5 electrically heated boats made ofmolybdenum, the following compounds were separately placed: 500 mg ofCompound (3), 200 mg ofN,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine(TPD), 200 mg of 4,4'-bis(2,2-diphenylvinyl)biphenyl (DPVBi), 200 mg of4,4'-bis[2-(4-(N,N-diphenylamino)phenyl)vinyl]biphenyl (DPAVBi), and 100mg of tris(8-hydroxyquinoline)aluminum (Alq).

After the pressure in the apparatus was reduced to 2×10⁻⁴ Pa, the boatcontaining Compound (3) was heated to deposit Compound (3) on thesubstrate, and a hole injecting layer having the thickness of 60 nm wasformed. Then, the boat containing TPD was heated to vaporize TPD, and ahole transporting layer having the thickness of 40 nm was formed. As thenext step, the boats containing DPVBi and DPAVBi were simultaneouslyheated to vaporize DPVBi and DPAVBi, and a mixed light emitting layerhaving the thickness of 40 nm was formed by the vapor deposition on thehole transporting layer [the ratio of the two mixed components was asfollows: DPVBi:DPAVBi=40:1 (ratio by weight)]. As the final step, theboat containing Alq was heated to deposit Alq on the light emittinglayer, and an electron injecting layer having the thickness of 20 nm wasformed.

Then, the product obtained above was taken out of the vacuum chamber,and a mask made of stainless steel was placed on the above electroninjecting layer. The combined product was fixed again to the substrateholder. Into a basket made of tungsten, 0.5 g of silver wire was placed,and 1 g of magnesium ribbon was placed into another boat made oftungsten. The pressure in the vacuum chamber was then reduced to 1×10⁻⁴Pa, and magnesium and silver were vapor deposited simultaneously at therates of vapor deposition of 1.8 nm/sec and 0.1 nm/sec, respectively, toprepare a mixed electrode of magnesium and silver.

The voltage of 8 V was applied to the obtained device by connecting theITO electrode of the prepared device to a positive electrode (+) and thecathode made of the magnesium-silver alloy to a negative electrode (-)to test emission of light, and a uniform light of blue color wasobtained. The following initial properties were obtained by applicationof the voltage of 8 V: the density of electric current: 3.9 mA/cm², theluminance: 170 cd/m², and the efficiency of light emission: 1.71lumen/W. When the initial luminance was adjusted to 100 cd/m², and thedevice was continuously driven at a constant electric current under adry nitrogen, the half-life time (the time before the luminance reachesone half of the initial value) was found to be 1500 hours.

Comparative Example 5

An organic electroluminescence device was prepared in accordance withthe same procedures as those conducted in Example 15 except that4,4',4"-tris(3-methylphenylphenylamino)triphenylamine (MTDATA, thecompound described in the specification of Japanese Patent ApplicationLaid-Open No. Heisei 4(1992)-308688) was used for the hole injectinglayer in place of Compound (3) used in Example 15.

The voltage of 8 V was applied to the obtained device in accordance withthe same method as that used in Example 15 to test emission of light,and a uniform light of blue color was obtained. The following initialproperties were obtained by application of the voltage of 8 V: thedensity of electric current: 4.0 mA/cm², the luminance: 140 cd/m², andthe efficiency of light emission: 1.37 lumen/W. When the initialluminance was adjusted to 100 cd/m², and the device was continuouslydriven at a constant electric current under a dry nitrogen, thehalf-life time was found to be 800 hours. This device had a life clearlyinferior to that of the device prepared in Example 15.

EXAMPLE 16

An organic electroluminescence device was prepared in accordance withthe same procedures as those conducted in Example 15 except thatCompound (20) was used in place of Compound (3) used in Example 15.

The test of emission of light was conducted in accordance with the samemethod as that used in Example 15, and the following initial propertieswere obtained by application of the voltage of 8 V: the density ofelectric current: 4.2 mA/cm², the luminance: 172 cd/m², and theefficiency of light emission: 1.61 lumen/W. When the initial luminancewas adjusted to 100 cd/m², and the device was continuously driven at aconstant electric current under a dry nitrogen, the half-life time wasfound to be 1300 hours.

EXAMPLE 17

An organic electroluminescence device was prepared in accordance withthe same procedures as those conducted in Example 15 except thatCompound (36) was used in place of Compound (3) used in Example 15.

The test of emission of light was conducted in accordance with the samemethod as that used in Example 15, and the following initial propertieswere obtained by application of the voltage of 8 V: the density ofelectric current: 4.0 mA/cm², the luminance: 168 cd/m², and theefficiency of light emission: 1.65 lumen/W. When the initial luminancewas adjusted to 100 cd/m², and the device was continuously driven at aconstant electric current under a dry nitrogen, the half-life time wasfound to be 1400 hours.

EXAMPLE 18

An organic electroluminescence device was prepared in accordance withthe same procedures as those conducted in Example 15 except thatCompound (43) was used in place of Compound (3) used in Example 15.

The test of emission of light was conducted in accordance with the samemethod as that used in Example 15, and the following initial propertieswere obtained by application of the voltage of 8 V: the density ofelectric current: 4.0 mA/cm², the luminance: 170 cdlm², and theefficiency of light emission: 1.71 lumen/W. When the initial luminancewas adjusted to 100 cd/m², and the device was continuously driven at aconstant electric current under a dry nitrogen, the half-life time wasfound to be 1500 hours.

EXAMPLE 19

An organic electroluminescence device was prepared in accordance withthe same procedures as those conducted in Example 15 except thatCompound (57) was used in place of Compound (3) used in Example 15.

The test of emission of light was conducted in accordance with the samemethod as that used in Example 15, and the following initial propertieswere obtained by application of the voltage of 8 V: the density ofelectric current: 4.1 mA/cm², the luminance: 167 cd/m², and theefficiency of light emission: 1.60 lumen/W. When the initial luminancewas adjusted to 100 cd/m², and the device was continuously driven at aconstant electric current under a dry nitrogen, the half-life time wasfound to be 1400 hours.

EXAMPLE 20

An organic electroluminescence device was prepared in accordance withthe same procedures as those conducted in Example 15 except thatCompound (70) was used in place of Compound (3) used in Example 15.

The test of emission of light was conducted in accordance with the samemethod as that used in Example 15, and the following initial propertieswere obtained by application of the voltage of 8 V: the density ofelectric current: 3.9 mA/cm², the luminance: 157 cd/m², and theefficiency of light emission: 1.58 lumen/W. When the initial luminancewas adjusted to 100 cd/m², and the device was continuously driven at aconstant electric current under a dry nitrogen, the half-life time wasfound to be 1300 hours.

INDUSTRIAL APPLICABILITY

As described in the above, the organic electroluminescence device of thepresent invention has little possibility of dielectric breakdown afterstorage for a long time, shows a remarkably high efficiency of lightemission, and is advantageously used as a light emitting device invarious types of display apparatus.

The thin film of the present invention shows very excellent holeinjecting and transporting properties and is advantageously used fororganic electroluminescence devices as well as other organic devices andphotosensitive films in the electronic photography.

The triamine compound of the present invention is a novel compound andprovides an organic electroluminescence device having a long life andshowing an excellent stability of light emission when the triaminecompound is used for the device.

We claim:
 1. An organic electroluminescence device which comprises anorganic layer at least comprising a layer of a hole transporting zoneand a layer of a light emitting zone and a pair of electrodes disposedon both sides of the organic layer, wherein the layer of a holetransporting zone at least comprises a hole injecting layer and a holetransporting layer, and the hole injecting layer contains a compoundrepresented by general formula (I): ##STR393## wherein Ar¹ to Ar⁵represent each an aryl group having 6 to 18 core carbon atoms which isunsubstituted or substituted with an alkyl group, an alkoxy group, vinylgroup, or styryl group, and may be the same with each other or differentfrom each other and is in contact with an anode.
 2. An organicelectroluminescence device according to claim 1, wherein Ar¹ to Ar⁵ ingeneral formula (I) represent each an aryl group having 6 to 18 carbonatoms which is unsubstituted or substituted with an alkyl group, analkoxy group, vinyl group, or styryl group.
 3. An organicelectroluminescence device according to claim 1, wherein the holetransporting layer contains a compound represented by general formula(II): ##STR394## wherein X represents a single bond, methylene group,phenylene group, biphenylene group, --O--, --S--, or a group representedby any of: ##STR395## and Ar⁶ to Ar¹⁰ represent each an aryl grouphaving 6 to 18 core carbon atoms which is unsubstituted or substitutedwith an alkyl group, an alkoxy group, vinyl group, or styryl group, andmay be the same with each other or different from each other.
 4. Anorganic electroluminescence device according to claim 3, wherein Ar⁶ toAr¹⁰ in general formula (II) represent each an aryl group having 6 to 18carbon atoms which is unsubstituted or substituted with an alkyl group,an alkoxy group, vinyl group, or styryl group.
 5. An organicelectroluminescence device according to claim 1, wherein the holeinjecting layer and the hole transporting layer have each a thickness of5 nm to 5 μm.
 6. An organic electroluminescence device according toclaim 3, wherein the hole injecting layer and the hole transportinglayer have each a thickness of 5 nm to 5 μm.
 7. An organic thin filmcomprising two layers which are a layer containing a compoundrepresented by general formula (I) and having a thickness of 5 nm to 5μm and a layer containing a compound represented by general formula (II)and having a thickness of 5 nm to 5 μm wherein general formula (I) is asfollows: ##STR396## where Ar¹ to Ar⁵ represent each an aryl group having6 to 18 core carbon atoms which is unsubstituted or substituted with analkyl group, an alkoxy group, vinyl group, or styryl group, and may bethe same with each other or different from each other;and whereingeneral formula (II) is: ##STR397## where X represents a single bond,methylene group, phenylene group, biphenylene group, --O--, --S--, or agroup represented by any of: ##STR398## and Ar⁶ to A¹⁰ represent each anaryl group having 6 to 18 core carbon atoms which is unsubstituted orsubstituted with an alkyl group, an alkoxy group, vinyl group, or styrylgroups, and may be the same with each other or different from eachother.
 8. A triamine compound represented by general formula (III):##STR399## wherein Ar¹ to Ar⁴ represent each an aryl group having 6 to18 core carbon atoms which is unsubstituted or substituted with an alkylgroup, an alkoxy group, vinyl group, or styryl group and may be the samewith each other or different from each other, and Ar⁵ representsbiphenyl group which is unsubstituted or substituted.
 9. A triaminecompound according to claim 8, wherein Ar⁵ in general formula (III)represents an aryl group represented by: ##STR400## wherein R representshydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy grouphaving 1 to 6 carbon atoms, or phenyl group, n represents an integer of0 to 5, and when a plurality of R are present, the plurality of R may bethe same with each other or different from each other, and Ar¹ to Ar⁴represent each an aryl group represented by any of: ##STR401## whereinR¹ to R⁵ represent each hydrogen, an alkyl group having 1 to 6 carbonatoms, an alkoxy group having 1 to 6 carbon atoms, or phenyl group, mrepresents an integer of 0 to 5, p represents an integer of 0 to 4, qrepresents an integer of 0 to 5, x represents an integer of 0 to 3, yrepresents an integer of 0 to 4, and when a plurality of R¹, R², R³, R⁴,or R⁵ are present, the plurality of R¹, R², R³, R⁴, or R⁵ may be thesame with each other or different from each other.
 10. The holetransporting layer of claim 3, wherein said compound represented bygeneral formula (II) is: ##STR402##